And as we will not hear the negro's argument about the sun, so we may abstain from arguing about protoplasm. We may say that we cannot weigh the evidence, that we do not know enough. Without denying the proposition we may withhold our assent; or, on the other hand, we may assent without grasping the proof, we may accept the proposition on authority. In either case we acknowledge a modification of this test of sufficiency. Proof is practically sufficient when it wins the general assent of those capable of understanding it.

112. Below this degree of sufficiency are several degrees of force to which is commonly given the name of proof. Loosely a proposition is said to be proved when a fair degree of probability is made out for it.

Mary Queen of Scots was an accomplice in the murder of Darnley. The Man with the Iron Mask was the brother of Louis XIV. Swift married Stella. These propositions cannot be proved at all; nor can they be disproved. The evidence is simply insufficient. What can be proved to practical sufficiency is: Mary Queen of Scots was probably innocent of the murder of Darnley. The Man with the Iron Mask probably was not the brother of Louis XIV. Swift probably married Stella. So with most questions of past fact, as of the objective reality of the visions of Joan of Arc; that they remain in dispute suggests that the evidence is insufficient for their settlement.

A nearer approach to sufficiency may often be attained for propositions concerning past right, justice, expediency, benefit. Webster was justified in his attitude toward the Clay Compromise. Henry VIII. was not justified in suppressing the monasteries. The administration of Andrew Jackson did more harm than good to this country. The system of Indian agencies is a mistake. Napoleon III. was personally responsible for the Franco-Prussian War. These propositions may be main

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tained or attacked with more nearly conclusive proof. But was the United States justified in the Mexican War? the Reformation proved, on the whole, a blessing to mankind? These questions are more hotly discussed and farther from conclusion.

They are more hotly discussed because they bear somewhat on the present and the future. Of propositions that look entirely to the present and future, that express what we conceive to be our rights and duties, our privileges and opportunities, proof may mean no more than the showing of evidence stronger than can be shown for the counter-proposition. The test of sufficiency thus becomes practically an adversary's analysis in refutation. These questions are perpetually in debate; and anything worthy to be called proof of them is reached but slowly. That is implied in calling them live questions or living issues. The propositions that frame them not only cannot be proved absolutely; they cannot even be shown to have that high degree of probability which is attainable for the theories of natural science. We cannot be certain about them as we are certain about the recurrence of comets, or even of the guilt of Napoleon III.

Yet we may support them with great force of argument. We may be persuaded and persuade others that this or that is the sounder public policy; that the United States ought to develop a merchant marine by subsidies, that railroads should not be owned by the State, that trades unions should be restricted by federal law, that there should be a national divorce law. These propositions being of the stuff of actual debate, in each case we have in mind to prevail over the counter-proposition held by opponents. The force of our proof is not absolute, but relative; the probability of our proposition we conceive to be not merely strong, but relatively stronger. Thus we set out to prove that our college should put a crew on the water. Aware that the lack of a crew would not subvert morality, nor even damage scholar

ship, we are yet persuaded "for good and sufficient reasons" that it is better to have a crew. Thus, also, we have the weightiest practical reasons to show that our city should establish a certain system of drainage, or our state separate the election of state officials from those of federal officials. In a certain sense these propositions cannot be proved, - if they could be, we should hardly have to argue; but they can be proved in the sense that our fellow-students or fellow-citizens can be convinced of their expediency. Men can be won to agree to them.

113. Though this lower range of sufficiency is the proper domain of persuasion, it should not, therefore, be said that persuasion is not concerned with truth. Our view of truth in matters of common argument we know to be incomplete. It grows; and toward its growth no small work is done by persuasion. And again, though any argument, if pushed far enough, may involve truth, involve certainties, we do not usually push an argument so far. The conclusions that in matters of common argument fall short of demonstration, do so partly for the very reason that they formulate, not certitudes, but opinions. They may be opinions very strongly held; we may say we are certain of them, but we then use the word certain loosely. man is certain of his creed in religion; he is also certain of his creed in politics; but the word may not express the same attitude of mind in the one case as in the other. Inquiry may show that he holds the one set of propositions to be absolutely true, to be irrefragable; the other set to be very highly probable, to be very strong, or perhaps only to be far stronger than the creed of the other party.

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When the proposition frames, not opinion, but certitude, it may still be unnecessary to produce complete demonstration. Whether certitude without complete demonstration is reasonable; whether, that is, it is reasonable to hold absolute truth without being able to exhibit absolute proof, - this is the inquiry of Newman's Grammar of Assent, to which, and to James's The Will to Believe, the inquirer is referred once for all. Newman's detailed application to religion is in fact the practical application. Except in religion, absolute truth is not for most men of real concern.

Persuasion, then, moves for the most part in probabilities, in matters about which we feel more than we know; and it so moves, not as though truth were subjective, but because in so many of our affairs, unable to be certain, we must proceed upon probabilities. As we learn more we revise our judgments, we reach higher and higher probability, nearer and nearer approximations to truth; and in this process an important part is played by persuasion. Thus, in politics, only time gives us the truth; but meanwhile, as one proposition after another is settled, it passes from discussion, and the others that become instant are only less doubtful than their predecessors were. Among these is persuasion, always of the living present, statesman and demagogue contending for the minds of men.

But since persuasion, more perhaps than any other kind of composition, takes colour from its material, rising with its subject, it is likely to be highest, to reach the pitch of eloquence, when it presents the highest motives, the weightiest sanctions, the final obligations. So modern eloquence is found oftenest, perhaps, in the pulpit. There, too, persuasion is devoted largely to winning assent to authority, to moving men, not indeed

without reason, but, since the hearers are not commonly in a position to measure the proof, without proof. With and without proof, persuasion, though having its usual concern with probabilities, finds its high concern in truth. Its journey-work is to win assent to probabilities; its great opportunity is to help men toward certitudes.

d. Refutation

114. Refutation is not a separate kind of argument, but simply a separate application. It is essentially the subjection of an opponent's argument to destructive analysis. As such, it is prepared along with the direct. argument for one's own side; for the only adequate preparation of one's own side includes knowing the other side as well. The fundamental questions in refutation (§ 134) are: How do you know? and What of it?1 That is, refutation, (1) negatively, (a) denies premises, either absolutely or in the form in which they are stated, (b) attacks the processes of argument as fallacious, (c) attacks the sufficiency of the proof as a whole; or (2) positively, exhibits counter-propositions as more probable; i.e. more reasonable, practicable, or just.

I. REFUTATION OF PREMISES

115. Absolute denial of premises, though not often feasible, is of course final.

To some one that defended his questionable practices by the proposition, "A man must live," Dr. Johnson made the famous retort, "Sir, I do not see the necessity." And again,

1 The phraseology is borrowed from the teaching of Professor William G. Sumner.